Communication channels or paths in a communication network typically have a specified maximum bandwidth which limits their capacity to carry traffic. Some types of connections such as MPLS LSPs allow bandwidth to be reserved so that a customer may be guaranteed sufficient bandwidth to transmit data packets at a required rate. Before allowing a requested connection, a connection admission controller determines whether the requested bandwidth is available. The requested bandwidth (which is typically requested in kilobits per second) is based on the anticipated payload, i.e. the data portion of the packets concerned. On receipt of the requested bandwidth, the connection admission controller applies a bandwidth expansion factor to the requested bandwidth to take account of the header portion of the packet which necessarily requires additional bandwidth. The bandwidth expansion factor applied by the connection admission controller is typically a constant value, which for example, is 1.2 for LSPs.